The overall goal of this 2 year proposal is to examine the association of glycemic load (GL), derived from 24-hour dietary recalls, with body weight and blood lipids (including total cholesterol, LDL, HDL, and triglycerides), and to study seasonal and short-term variation of GL in a free-living healthy population. Results from short-term experimental studies and a limited number of observational studies suggest that GL, a measure of the quality and quantity of carbohydrate in foods, may be related to body weight and serum lipids, and GL potentially should be considered in dietary recommendations. However, neither the glycemic index (GI) nor GL is considered in the dietary guidelines of the American Heart Association, the U.S Department of Agriculture, or the American Diabetes Association. We will use dietary data collected from the Seasonal Variation in Blood Cholesterol Levels (SEASONS) (NHLBI: R01-HL52745) (1. Ockene - P.I.) study, in which 641 healthy adults in central Massachusetts were followed quarterly (baseline and four consecutive quarters: five sampling points in all) during this a one-year observational study. A total of fifteen 24-hour dietary and physical activity recalls were collected for each subject, with serum lipids and body weight measured five times. Serum lipids and body weight were measured once per quarter and three 24-hour recalls were administered (two weekdays and one weekend day) per quarter. If GL is found to be associated with body weight and blood lipids, a randomized clinical trial will be designed to evaluate the effects of a GL-based nutritional intervention program on hyperlipidemic patients. The methodology of this proposed study will involve several steps: 1) Data summarization of 9,067 24- hour diet recall records, 2) GL calculation and calculation of overall GI index, 3) Analysis of the relationship of GL to body weight and blood lipids, 4) Estimation of seasonal and short-term variations in GL, 5) Analysis of GL by meal type and identification of the top ten food contributors, 6) Analysis of the association of overall GI with body weight and blood lipids, and 7) Final report and manuscript preparation.